README

This application implements a payment system which satisfies following requirements

Application Setup:

Ruby v3.2.2
Rails v7.1.0
Jsubundler - bun
GoodJob - For background jobs
Interactor - For service objects
API Authentication - Based on Bearer token
Linting - Rubocop
Functional automation testing - Capybara
Database - Postgresql

How to Run Application

Install Ruby v3.2.2
Install postgresql
Install all gems using bundle install
Set up javascript packags using bun install
Set up database bin/rails db:create db:migrate
Import users
- Sample csv file - tmp/user_import.csv
- rails import:users[<path_to_csv_file>]
Routes

Prefix Verb   URI Pattern                                                                                       Controller#Action
                                    root GET    /                                                                                                 pages#home
                                good_job        /good_job                                                                                         GoodJob::Engine
                        new_user_session GET    /users/sign_in(.:format)                                                                          devise/sessions#new
                            user_session POST   /users/sign_in(.:format)                                                                          devise/sessions#create
                    destroy_user_session DELETE /users/sign_out(.:format)                                                                         devise/sessions#destroy
                               merchants GET    /merchants(.:format)                                                                              merchants#index
                                         POST   /merchants(.:format)                                                                              merchants#create
                            new_merchant GET    /merchants/new(.:format)                                                                          merchants#new
                           edit_merchant GET    /merchants/:id/edit(.:format)                                                                     merchants#edit
                                merchant GET    /merchants/:id(.:format)                                                                          merchants#show
                                         PATCH  /merchants/:id(.:format)                                                                          merchants#update
                                         PUT    /merchants/:id(.:format)                                                                          merchants#update
                                         DELETE /merchants/:id(.:format)                                                                          merchants#destroy
                            transactions GET    /transactions(.:format)                                                                           transactions#index
                                         POST   /transactions(.:format)                                                                           transactions#create
                         new_transaction GET    /transactions/new/:transaction_type(.:format)                                                     transactions#new
                              pages_home GET    /pages/home(.:format)                                                                             pages#home

API Routes

api POST   /api/transactions/:transaction_type(.:format)

Sample API call

If an active merchant with id:<ACTIVE_MERCHANT_ID> and token <MERCHANT_API_TOKEN>exists then api call to crete transaction would looke like this:

curl -X POST -H "Authorization: Bearer MERCHANT_API_TOKEN" -H "Content-Type: application/json" -d '{ "merchant_id": "ACTIVE_MERCHANT_ID", "customer_email": "test@example.com", "customer_phone": "1234567890", "txn_amount": 300 }' http://localhost:3000/api/transactions/authorize

Sample api response

{"uuid":"c3c365f7-9cec-4f0b-b431-05e5a5800c1d","status":"approved","customer_email":"test@example.com","customer_phone":"1234567890","merchant_id":7,"reference_transaction_id":null,"transaction_type":"AuthorizeTransaction","created_at":"2023-11-02T22:09:08.544Z","updated_at":"2023-11-02T22:09:08.570Z","amount":300.0}

API Token Generated for every merchant on creation
Test cases
- Implemented using rspec, shoulda matchers and capybara
- To run test suit, run command rspec spec
Integration test cases
- spec/system/integration/payment_system_spec.rb

Relations:

1.1. Ensure you have merchant and admin user roles (UI) 1.2. Merchants have many payment transactions of diﬀerent types 1.3. Transactions are related (belongs_to)

You can also have follow/referenced transactions that refer/depend to/on the initial transaction Authorize Transaction -> Charge Transaction -> Refund Transaction Authorize Transaction -> Reversal Transaction

Only approved or refunded transactions can be referenced, otherwise the submitted transaction will be created with status error
Ensure you prevent a merchant from being deleted unless there are no related payment transactions
Use validations for: uuid, amount > 0, customer_email, status
Use STI
Transaction Types
1. Authorize transaction - has amount and used to hold customer's amount
2. Charge transaction - has amount and used to conﬁrm the amount is taken from the customer's account and transferred to the merchant
3. The merchant's total transactions amount has to be the sum of the approved Charge transactions
4. Refund transaction - has amount and used to reverse a speciﬁcamoun (whole amount) of the Charge Transaction and return it to the customer -- Transitions the Charge transaction to status refunded
5. The approved Refund transactions will decrease the merchant's total transaction amount -- Reversal transaction - has no amount, used to invalidate the Authorize Transaction -- Transitions the Authorize transaction to status reversed

Design patterns implemented